This is when your "dog" (Boner, Hard-on) gets sprayed by a "Skunk" (Gay man) you have cum shot all over your dick. This is a popular finishng move for two gay men having intercourse

A great example of this is when gay man number 1 = Terry is having anal intercourse with gay man number 2 = Sean, before Terry errupts in Seans butt region, Terry pulls out and flips Sean over to ejaculate his Semen all over Seans Penis